Semiconductor device and method for manufacturing the same

ABSTRACT

The present invention provides a semiconductor device having a structure that can be mounted on a wiring substrate, as for the semiconductor device formed over a thin film-thickness substrate, a film-shaped substrate, or a sheet-like substrate. In addition, the present invention provides a method for manufacturing a semiconductor device that is capable of raising a reliability of mounting on a wiring substrate. One feature of the present invention is to bond a semiconductor element formed on a substrate having isolation to a member that a conductive film is formed via a medium having an anisotropic conductivity.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a semiconductor device that is thin andlightweight, and a manufacturing method thereof. Specifically, asemiconductor device using a substrate having a thin thickness or afilm-shaped substrate, and a manufacturing method thereof.

2. Description of the Related Art

In recent years, cellular phones spread with the progress ofcommunication technology. It is expected that cellular phones transmitmoving image and more communication are expected more in future. On theother hand, laptop computers for mobile have been produced due to theweight saving. A large number of personal digital assistances referredto as PDA that begin from electronic notebook have been produced, anddiffused. Moreover, most of such personal digital assistances are eachmounted with a flat panel display by the development of display devices.

In such a display device, the brightness around the display device isdetected, and its display luminance is adjusted. Thus, by detecting thebrightness around the display device to obtain moderate displayluminance, useless electric power can be reduced. For example, such anoptical sensor apparatus for controlling luminance is used for cellularphones and laptop computers (for example, Patent Document 1).

As a material for an optical sensor, semiconductor is mainly used.Silicon is taken as a representative example of a semiconductormaterial. An optical sensor using silicon is formed by single crystalsilicon or polysilicon, or amorphous silicon. An optical sensor usingsingle crystal silicon or polysilicon has the highest sensitivity in aninfrared region at around 800 nm, and has sensitivity at most around1100 nm. Therefore, in the case that the optical sensor using singlecrystal silicon or polysilicon senses white fluorescent light thathardly include a spectrum of an infrared region and sunlight that has awide spectrum from an ultraviolet region to an infrared region, there isa problem that sensing result of each light is different while actualbrightness is the same.

On the other hand, an optical sensor using amorphous silicon hardly hassensitivity against light in an infrared region, and has the highestsensitivity in a range of approximately 500 to 600 nm that is central ofwavelength of visible light region. In addition, the optical sensorusing amorphous silicon has sensing characteristics that is like humanvisibility. Therefore, amorphous silicon is preferably used for theoptical sensor.

A plastic substrate is thin and lightweight. Therefore, a wiringsubstrate that is mounted with an optical sensor formed over the plasticsubstrate and electronic devices using the wiring substrate can bemanufactured to be thin and downsized.

Moreover, in the case of manufacturing an optical sensor usingfilm-shaped substrate, a Roll-To-Roll method can be used. Therefore, theproductivity of such optical sensor is improved.

-   [Patent Document 1] Japanese Patent Laid-Open No. 2003-60744    bulletin

However, a connection terminal of a wiring substrate cannot be formed ona side face of a plastic substrate because of its thin thickness.Therefore, the connection terminal is formed on one face, that the facethat faces the wiring substrate. The wiring substrate and an opticalsensor are fixed by only one face via a conductive material. The area ofthe face is small, thus, there is a problem that the mounting intensityis weaker than that of a side electrode structure.

In addition, it is difficult to see a junction between an electrodeterminal of the optical sensor and an electrode pad to judge whetherthey connect to each other surely, because a region where the wiringsubstrate is connected to the optical sensor is the lower part of asubstrate of the optical sensor.

Moreover, a film-shaped optical sensor is hard to mount over the wiringsubstrate because of its flexibility.

SUMMARY OF THE INVENTION

In view of the foregoing, it is an object of the present invention toprovide a semiconductor device having the structure that can be mountedon a wiring substrate and is formed over a thin substrate, a film-shapedsubstrate, or a sheet-like substrate. It is another object of thepresent invention to provide a manufacturing method of a semiconductordevice that can enhance the reliability of mounting the semiconductordevice over a wiring substrate.

According to one aspect of the present invention, a manufacturing methodof a semiconductor device is provided that comprises bonding asemiconductor element formed over a substrate having insulation to amember that a conductive film is formed via a medium having anisotropicconductivity. Note that it is preferable that the member provided with aconductive film is a member in which a conductive film is formed at edgeportions, that is, the conductive films each of which is formed over atleast one face of the member.

As the medium having anisotropic conductivity, a medium dispersed withconductive particles in a paste form or a film-shaped can be nominated.

As the substrate having insulation, a thin substrate that has a filmthickness from 0.1 to 1 mm, a film-shaped substrate, and a sheet-likesubstrate can be nominated. As a representative example, a glasssubstrate, a plastic substrate, and a substrate formed by organic resin,and the like, can be nominated.

As the method for bonding the substrate having insulation and the memberthat the conductive film is formed via a medium having anisotropicconductivity, a pressure bonding method that adds load partially isgiven. In this case, it is preferably to apply load to the substrate andthe member, and the while adding heat or ultrasonic wave thereto. Whenpressure bonding is carried out while applying ultrasonic wave,vibrational energy is transmitted to a conductive particle from each ofthe terminal, that is, an electrode terminal and a connection terminal.As a result, friction is generated between each of the terminal and theconductive particle, and joining of each of the terminal and theconductive particle is promoted by means of energy due to the frictionalheat. Therefore, joining at low temperature is possible.

According to one aspect of the present invention, a semiconductor deviceis provided that has a substrate formed over a semiconductor element anda substrate provided with a conductive film at the edge portions (aninterposer), and either surface of the substrate provided with thesemiconductor element and the substrate provided with the conductivefilm are fixed to each other via an anisotropic conductive member.

The substrate having insulation and the interposer are fixed to eachother via the semiconductor element and the anisotropic conductivemember.

It is preferable that an area of the substrate provided with thesemiconductor element and an area of the interposer is approximately thesame. Moreover, the area of the substrate provided with thesemiconductor element may be larger than the area of the interposer. Inthis case, a region provided with the semiconductor element isincreased. Therefore, a further integrated semiconductor device can bemanufactured. In addition, the area of the interposer may be larger thanthe area of the substrate provided with the semiconductor element. Inthis case, an area to be bonded to a wiring substrate is increased, andso the stability is increased in the mounting portion.

As a result, a semiconductor device can be mounted over the wiringsubstrate with high reliability.

The conductive film formed on an interposer is a connection terminal,and serves as a side electrode. The conductive film is formed toelectrically connected to an electrode pad formed on a substrate formounting a semiconductor device, for example, a wiring substrate. Theconductive film is electrically connected to the electrode pad on awiring substrate via a conductive paste to be fixed. Note that, ananisotropic conductive adhesive agent or an anisotropic conductive filmcan be used instead of the conductive paste.

The semiconductor element has a semiconductor film, and thesemiconductor film is formed from an inorganic material or an organicmaterial.

As a representative example of the semiconductor film formed from theinorganic material, a silicon film, a gallium film, a silicon film addedwith gallium, and a silicon carbide film, and the like can be given. Inaddition, as a representative example of the semiconductor film formedfrom the organic material, polymer or oligomer as typified by conjugatedpolymer, for example, polyphenylene vinylene derivatives, polyfluorenederivatives, polythiophene derivatives, polyphenylene derivatives, andthese copolymer, oligo phenylenes, oligothiophenes can be given.Moreover, as a low molecular weight compound material, pentacenes,tetracenes, copper phthalocyanines, perfluorinated phthalocyanines (F16H2PC), perylene derivatives are given.

In the present invention, in case that the semiconductor device is anoptical sensor, a photoelectric conversion device, or a solar battery,the semiconductor film is formed from a film having silicon. As arepresentative example of the semiconductor film having silicon, asilicon film, silicon germanium film, a silicon carbide film, or thesePN junction film, PIN junction film can be nominated. Note that, it isdesirable that an I layer of the PN junction film and the PIN junctionfilm is formed with an amorphous silicon layer

Moreover, in a light receiving portion of the optical sensor, thephotoelectric conversion device, or the solar battery, an amplifiercircuit to amplify the quantity of detected light received in the lightreceiving portion, or an amplification element may be provided. As arepresentative example of the amplifier circuit, a current mirrorcircuit formed from a TFT can be nominated. As a representative exampleof the amplification element, an operational amplifier can be nominated.

Moreover, as the semiconductor device of the present invention, anintegrated circuit that is formed from a TFT can be nominated, inaddition to the optical sensor, the photoelectric conversion device, andthe solar battery.

As a representative example of the integrated circuit formed by usingTFT, memory, CPU, and the like can be nominated.

In the semiconductor device according to the present invention, thesemiconductor element can be electrically connected to a connectionterminal (side electrode) of the interposer, therefore, an area to bejoined to the wiring substrate is increased. That is, a joining mode canbe checked with eyes, in addition that mounting intensity can be raised.

Moreover, the connection of the semiconductor element and the interposeris strong because these two members are bonded in an aspect of entiresurface facing each other. Moreover, the cost can be reduced becausethese two members are connected by means of resin. In addition, resinhas high fixing strength, so the semiconductor device having highbreaking strength can be manufactured.

Furthermore, even if the substrate provided with the semiconductorelement having flexibility like a sheet-like substrate or a film-shapedsubstrate, the semiconductor device according to the present inventioncan be mounted on a wiring substrate. In addition, in case that the heatresistance of the substrate provided with the semiconductor element islow, especially in case that the substrate having the heat resistancethat is hard to withstand treatment for mounting the semiconductordevice on the wiring substrate, the semiconductor device can be mountedover the wiring substrate by forming the interposer by a member havingheat resistance. Therefore, the semiconductor element that is formedover a substrate having flexibility can be mounted over the wiringsubstrate by Roll-To-Roll method.

Hereinafter, embodiment mode of the present invention is described withreference to the drawings. However, the present invention can be carriedout in many different modes, and it is easily understood by those whoare in the art that embodiments and details herein disclosed can bemodified in various ways without departing from the scope and spirit ofthe present invention. Therefore, it should be noted that thedescription of this embodiment mode should not be interpreted aslimiting the present invention. Hereinafter, this embodiment mode isdescribed using an optical sensor as a representative example of asemiconductor device, but is not limited to this, and may be applied tothe integrated circuit or the like that is formed by using aphotoelectric conversion element, the solar battery, and TFT.

These and other objects, features and advantages of the presentinvention will become more apparent upon reading of the followingdetailed description along with the accompanied drawings.

BRIEF DESCRIPTION OF THE DRAWING

FIGS. 1A and 1B are explanatory perspective and cross-section views fora semiconductor device according to the present invention;

FIG. 2 is an explanatory cross-sectional view for a semiconductor deviceaccording to the present invention that is mounted on a wiringsubstrate;

FIG. 3 is an explanatory cross-sectional view for a semiconductor deviceaccording to the present invention;

FIGS. 4A and 4B are explanatory cross-sectional views for asemiconductor device according to the present invention;

FIGS. 5A to 5D are explanatory views for a manufacturing step of asemiconductor device according to the present invention;

FIGS. 6A to 6D are explanatory views for a manufacturing step of asemiconductor device according to the present invention; and

FIGS. 7A to 7D are explanatory views for a manufacturing step of asemiconductor device according to the present invention.

DETAILED DESCRIPTION OF THE INVENTION Embodiment Mode 1

An optical sensor of the present invention is described with referenceto FIGS. 1A and 1B.

FIG. 1A is a perspective view for showing an optical sensor 100. Theoptical sensor 100 is composed of a plastic substrate 101 provided witha semiconductor element (not shown in the figure), a heat-resistantsubstrate 105 (hereinafter, an interposer) provided with conductivefilms 106 and 107 at both ends portions of the heat-resistant substrate,and an adhesive agent 108 for bonding the plastic substrate 101 to theheat-resistant substrate 105 together.

FIG. 1B is a cross-sectional view taken along line (a)-(a′) of FIG. 1A.A semiconductor element 102 is formed over a plastic substrate 101, andelectrode terminals 103 and 104 that are leading out electrodes of thesemiconductor element are formed. In this embodiment mode, thesemiconductor element serves as a light receiving portion. Moreover,connection terminals (side electrodes) 106 and 107 are formed at bothends of the interposer 105. The light receiving portion over the plasticsubstrate and the interposer are bonded to each other via an anisotropicconductive adhesive agent 108. In addition, the electrode terminals 103and 104 and the connection terminals (side electrodes) 106 and 107 areelectrically connected to each other via conductive particles 110 and111 of an anisotropic conductive film.

As the plastic substrate, a plastic having a thickness of from 0.1 to 1mm, a film-shaped plastic, and a sheet-like plastic can be nominated.

As representative examples of the plastic substrate, a plastic substrateformed from PET (polyethylene terephthalate), PEN (polyethylenenaphthalate), PES (polyether sulfide), polypropylene, polypropylenesulfide, polycarbonate, polyetherimide, polyphenylene sulfide,polyphenylene oxide, polysulfone, or polyphthalamide, or a substrateincluding an organic material dispersed with inorganic particles ofseveral nanometers in diameter, or the like can be nominated. Inaddition, a surface of the plastic substrate is not required to be flat,and may be uneven or have a curved surface.

Moreover, instead of the plastic substrate, a glass substrate having athickness of from 0.1 to 1 mm, more preferably, 0.2 to 0.5 mm, or afilm-shaped glass or sheet-like glass can be used.

As examples of the interposer, a glass epoxy resin substrate, apolyimide substrate, a ceramic substrate, a glass substrate, an aluminasubstrate, an aluminum nitride substrate, and a metal substrate, or thelike is representatively given.

As a representative example of the anisotropic conductive adhesiveagent, adherent resin containing dispersed conductive particles (graindiameter: approximately of from 3 to 7 μm) such as epoxy resin andphenol resin is given. Moreover, the conductive particles (graindiameter: approximately of from 3 to 7 μm) are formed from one elementor a plurality of elements selected from the group consisting of gold,silver, copper, palladium, and platinum. In addition, particles in whichthe elements coat in a multilayer structure may be used.

Furthermore, conductive particles formed by resin coated with thin filmformed by one element or a plurality of elements selected from the groupconsisting of gold, silver, copper, palladium, and platinum may be used.

Moreover, instead of the anisotropic conductive adhesive agent, ananisotropic conductive film that is formed in film-shaped over a basefilm may be used by being pasted to the interposer, and then, the basefilm is taken off. The anisotropic conductive film is dispersed with theconductive particles that are similar to those dispersed to theanisotropic conductive adhesive agent.

As a material for the electrode terminals 103 and 104 that iselectrically connected to the light receiving portion, one elementselected from the group consisting of nickel (Ni), copper (Cu), zinc(Zn), palladium (Pd), silver (Ag), tin (Sn), platinum (Pt), and gold(Au), and more preferably, nickel (Ni), copper (Cu), silver (Ag),platinum (Pt), and gold (Au); or an alloy material including at least50% of the element may be nominated. Nickel (Ni), silver (Ag), palladium(Pd), platinum (Pt), or gold (Au) can be ohmic contact to a siliconsemiconductor layer and alloyed with solder, and can be used in a singlelayer. These metal are not always necessarily a single composition, andmay be an alloy composition including the metal as the main component.However, as used herein, the term “alloy” refers to an alloy includingat least 50% of base metal component.

As a material for the connection terminals (side electrodes) 106 and 107that are formed at the edge portions of the interposer, one elementselected from the group consisting of nickel (Ni), copper (Cu), zinc(Zn), palladium (Pd), silver (Ag), tin (Sn), platinum (Pt), and gold(Au), and more preferably, nickel (Ni), copper (Cu), silver (Ag),platinum (Pt), and gold (Au); or an alloy material including at least50% of the element may be nominated.

The semiconductor element includes a semiconductor film, and thesemiconductor film is formed from an inorganic material or an organicmaterial.

As a representative example of the semiconductor film formed from theinorganic material, a silicon film, a gallium film, a silicon film addedwith gallium, a silicon carbide film, and the like can be given. Inaddition, as a representative example of the semiconductor film formedfrom the organic material, polymer or oligomer as typified by conjugatedpolymer, for example, polyphenylene vinylene derivatives, poly fluorenesderivatives, poly thiophenes derivatives, polyphenylene derivatives, andthese copolymer, oligo phenylenes, oligothiophenes can be given.Moreover, as a low molecular weight compound material, pentacenes,tetracenes, copper phthalocyanines, perfluorinated phthalocyanines (F16H2PC), phthalocyanines, perylenes, and the like are given.

As a semiconductor device of this embodiment mode is the optical sensor,the semiconductor film is formed from a film having silicon. As arepresentative example of the semiconductor film having silicon, asilicon film, silicon germanium film, a silicon carbide film, or thesePN junction film, PIN junction film can be nominated. Note that, it isdesirable that an I layer of the PN junction film and the PIN junctionfilm is formed with an amorphous silicon layer.

In the semiconductor device according to the present invention, thesemiconductor element can be electrically connected to a connectionterminal (side electrode) of the interposer, therefore, an area to bejoined to the wiring substrate is increased. That is, a joining mode canbe checked with eyes, in addition that mounting intensity can be raised.Therefore, reliability in process can be raised. Moreover, thesemiconductor element is formed over the substrate, and a substrate areaand the region that serves as the semiconductor element is approximatelyequal. Therefore, the semiconductor element can be highly integratedover the wiring substrate or the like.

Moreover, connection of the semiconductor element and the interposer isstrong since these two members are bonded in an aspect of entire surfacefacing each other.

In addition, the semiconductor element is connected to the interposervia resin. Therefore, the cost can be reduced in case of using resin incomparison with using metallic paste such as solder. Moreover, resin hashigh fixing strength, so the semiconductor device having high breakingstrength can be manufactured.

Embodiment Mode 2

In this embodiment mode, a method for mounting of an optical sensorshown in Embodiment Mode 1 over a wiring substrate is described withreference to FIG. 2.

FIG. 2 is a cross-sectional view for showing that an optical sensor 100is mounted over a wiring substrate 201. An interposer 105 in whichconnection terminals (side electrodes) 106 and 107 are formed and asemiconductor element 102 (in this embodiment mode, a light receivingportion) that is formed on a plastic substrate 101 are bonded to eachother via an anisotropic conductive adhesive agent 108. Moreover,electrode terminals 103 and 104 of the light receiving portion and theconnection terminals (side electrodes) 106 and 107 that is formed atedge portions of the interposer is electrically connected to each othervia a conductive particle 109 that is included in the anisotropicconductive adhesive agent 108.

In addition, connection terminals (side electrodes) 106 and 107 that areformed on the interposer and electrode pads 202 and 203 on the wiringsubstrate are respectively connected to each other via soldering paste204 and 205.

In this embodiment mode, an optical sensor is mounted over a wiringsubstrate by reflow step. Specifically, a conductive paste is applied topredetermined area of electrode pad by screen printing or dispense, andthe optical sensor is attached thereon with mounter. Thereafter, theconductive paste is heated and melted at temperatures ranging of from250 to 350° C. Then, both of the electrode terminals of the opticalsensor and the connection terminals, and the electrode pads over thewiring substrate are connected electrically and mechanically to eachother.

As examples of heating method, infrared heating, vapor phase soldering,hot blast heating, heating on hot plate, and heating by laserirradiation, and the like are given.

Moreover, instead of mounting method by reflow step using conductivepaste, an optical sensor may be mounted over the wiring substrate bypartial pressure bonding using an anisotropic conductive adhesive agentor an anisotropic conductive film.

In the semiconductor device according to the present invention, thesemiconductor element can be electrically connected to a connectionterminal (side electrode) of the interposer, therefore, an area to bejoined to the wiring substrate is increased. That is, a joining mode canbe checked with eyes, in addition that mounting intensity can be raised.Therefore, reliability in process can be raised. Moreover, thesemiconductor element is formed over the substrate, and a substrate areaand the region that serves as the semiconductor element is approximatelyequal. Therefore, the semiconductor device can be highly integrated overthe wiring substrate or the like.

Moreover, the connection of the semiconductor element and the interposeris strong since these two members are bonded in an aspect of an entiresurface facing each other via resin.

In addition, since the semiconductor element and the interposer areconnected to each other by using resin, the cost can be reduced thanthat when metal paste is used. Moreover, resin has high fixing strength,and so the semiconductor device having high breaking strength can bemanufactured.

Embodiment Mode 3

In this embodiment mode, a light receiving portion of an optical sensorthat is a semiconductor element shown in embodiment mode 1 and 2 isdescribed with reference to FIG. 3 to FIG. 4B.

FIG. 3 is a cross-sectional view for showing an optical sensor 300 ofthe present invention. A first electrode 311, a light receiving portion302, and a second electrode 312 are formed over a plastic substrate 301.The first electrode is connected to a first electrode terminal 313, andthe second electrode is connected to a second electrode terminal 314.The first electrode terminal 313 and the second electrode terminal 314are electrically insulated with an interlayer insulating film 315therebetween. The first electrode terminal and the second electrodeterminal are terminals for connecting to a wiring on a wiring substrate.

In the case that light is incident from the plastic substrate 301 side,the first electrode is formed from a conductive film that ohmic contactwith a semiconductor layer formed from silicon is possible and that islight transmitting. Representatively, ITO (indium tin oxide alloy),indium oxide zinc oxide alloy (In₂O₃—ZnO), zinc oxide (ZnO), and indiumtin oxide alloy including silicon oxide, or the like can be used.Moreover, the second electrode is formed from a metal film that ohmiccontact with the semiconductor layer formed from silicon is possible. Asa representative example of this, one element selected from the groupconsisting of aluminum (Al), titanium (Ti), chrome (Cr), nickel (Ni),molybdenum (Mo), palladium (Pd), tantalum (Ta), tungsten (W), platinum(Pt), and gold (Au); or an alloy material including at least 50% of theelement are given. On the other hand, in case that light is incidentfrom the interlayer insulating film side, the first electrode is formedfrom a metal film that ohmic contact with the semiconductor layer formedfrom silicon is possible. A conductive film that ohmic contact with asemiconductor layer formed from silicon is possible and that is lighttransmitting is used for the second electrode.

The first electrode terminal 313 and the second electrode terminal 314are leading out electrodes, and are each a terminal to electricallyconnect the first electrode and the second electrode to an externalwiring. Therefore, the first electrode terminal and the second electrodeterminal are each formed from a material that is possible to beconnected to the first electrode, the second electrode, and a connectionterminal. Representatively, one element selected from the groupconsisting of nickel (Ni), copper (Cu), zinc (Zn), palladium (Pd),silver (Ag), tin (Sn), platinum (Pt), and gold (Au), and morepreferably, nickel (Ni), copper (Cu), silver (Ag), platinum (Pt), andgold (Au); or an alloy material including at least 50% of the elementare given.

The interlayer insulating film 315 is formed to electrically insulatethe electrode terminal that is the leading out electrode, in addition tosuppress deterioration by sealing the first electrode 311 and the secondelectrode 312, and the light receiving portion 302. The interlayerinsulating film can be formed from organic resin such as acryl,polyimide, polyamide, polyimidamide, and benzocyclobutene, or aninorganic material such as silicon oxide film, silicon nitride oxidefilm, and a silicon oxynitride film.

In addition, the structure of the optical sensor can be not only thecross-sectional view shown in FIG. 3 but also other structures. FIGS. 4Aand 4B each show cross-sectional views for showing the structure of anoptical sensor different from that illustrated in FIG. 3.

FIG. 4A is one example of a cross-sectional view for showing a lightreceiving portion of an optical sensor 300. The sensor is formed from alight receiving portion 302, a first electrode terminal 313 and a secondelectrode 312 each of which is in contact with the light receivingportion, an electrode terminal 314 that is connected to the secondelectrode. The sensor does not have a first electrode, which isdifferent from the light receiving portion of the optical sensor of FIG.3. Therefore, an area that the first electrode terminal 313 contactswith the light receiving portion 302 is increased, thus the number ofconnection sections (contact sections) is preferable to be large. Inthis structure, there is not a first electrode, thus there is an effectthat a transmittance of light that transmits from a substrate 301 can beenhanced, in addition that the number of steps can be reduced.

FIG. 4B is one example of a cross-sectional view for showing a lightreceiving portion of an optical sensor. The sensor is formed from alight receiving portion 332, a first electrode terminal 313 and a secondelectrode 312 each of which is in contact with the light receivingportion, an electrode terminal 314 that is connected to the secondelectrode. A light receiving layer is formed on entire surface of thesubstrate 301 without being patterned the light receiving layer, whichis different from the light receiving portion of the optical sensor ofFIG. 4A. Therefore, the light receiving layer can be formed withoutusing a mask, and it is not necessary to control position of the mask.Thus, yield can be improved.

In the semiconductor device according to the present invention, thesemiconductor element can be electrically connected to a connectionterminal (side electrode) of the interposer, therefore, an area to bejoined to the wiring substrate is increased. That is, a joining mode canbe checked with eyes, in addition that mounting intensity can be raised.Therefore, reliability in process can be raised.

Moreover, connection of the semiconductor element and the interposer isstrong because these two members are bonded in an aspect of entiresurface facing each other by resin. In addition, because thesemiconductor element and the interposer are connected to each other byusing resin, the cost can be reduced. Moreover, resin has high fixingstrength, thus the semiconductor device having high breaking strengthcan be manufactured. Furthermore, by forming the light receiving layerusing amorphous silicon, an optical sensor having sensingcharacteristics like human visibility can be formed.

Embodiment 1

Embodiment of the present invention is described by using FIG. 5A toFIG. 7D. FIG. 5A, FIG. 5C, FIG. 6A, FIG. 6C, FIG. 7A, and FIG. 7C aretop views for showing a substrate, and FIG. 5B, FIG. 5D, FIG. 6B, FIG.6D, FIG. 7B, and FIG. 7D are cross-sectional views for showing (b)-(b′)region in them.

As shown in FIGS. 5A and 5B, a semiconductor film is formed on a plasticsubstrate 601 with a plasma CVD apparatus. Here, a silicon semiconductorfilm 602 having respective conductive type p, i, and n is formed as thesemiconductor film. Herein, the I layer which is a light receivingportion has amorphous phase, and phase states of p and n are notconsidered. The film thickness of the I layer is fit in an illuminancerange of an intended element to be set in a range of 100 to 1000 nm. Inthis embodiment, a PEN film is used as the plastic substrate, and thesilicon semiconductor film is formed to have a thickness of 800 nmthereon.

Then, a contact hole 603 is formed like a point at a predeterminedportion in a laser scribe step in order that a p-type silicon film thatis in a lower portion of the formed semiconductor film is to be joinedwith a metal electrode formed in the next step as shown in FIGS. 5C and5D. In this step, it is preferably scribed to leave a p layer at thebottom of the contact hole, but it is difficult to control in the depthdirection by a laser, and thus, the contact hole may penetrate to thesurface of the plastic substrate to ensure a process margin.Accordingly, the actual contact portion is a small region in which thethickness of the p layer is exposed to a wall face of the contact hole,and thus, a large number of independent holes are formed to increase thecontacting area. Further, energy density of an edge and a center of alaser beam can be sequentially changed with a gentle slope bycontrolling the focus of a laser beam to defocus intentionally by usinga condensing optical system. Laser scribing is performed in this stateto generate a taper in a wall face of a scribed portion, therebyenlarging more contact areas. In this embodiment, a YAG laser having awavelength of 1.06 μm and a beam diameter (φ) of 60 μm is used to scanthe laser beam with an oscillating frequency of 1 kHz not to beoverlapped.

Then, as shown in FIGS. 6A and 6B, a first electrode 604 and a secondelectrode 605 are formed. A metal conductive film is formed to have asingle layer structure or a laminated structure as the first electrodeand the second electrode. As the film formation method, a sputteringmethod, a vapor deposition method or a plating method may be employed,or the methods are employed together. In the case of using a vapor phasemethod such as sputtering or vapor deposition, a desired electrode shapecan be obtained easily by using a metal mask. Two opening portions forone element are formed in the metal mask, and electrodes of the bothpoles are formed simultaneously. The metal mask, the plastic substrateand a plate-like magnet are set in this order to be overlapped with oneanother in a sputtering apparatus, and inhomogeneous of the electrodearea due to wrap-around deposited film is prevented by bonding the metalmask to the plastic substrate tightly. In the case of using a platingmethod, by conducting masking on resin in advance by screen printing inthe region where a metal electrode is not required, a desired electrodeshape can be obtained by a lift-off method after forming a metalelectrode. The first electrode and the second electrode 604 and 605ranging of 0.5 to 100 μm in thickness are formed under theabove-described conditions.

In this embodiment, an Ni metal is deposited by using a metal mask witha sputtering method. The metal mask is 0.1 mm in thickness and is formedfrom nickel. The metal mask and the plastic substrate are set in thesputtering apparatus in the state that the metal mask and the plasticsubstrate are tightly bonded to each other via a plat-like magnet. Afilm that is 1.5 μm and is formed from nickel is formed by using a Nitarget of six inches in diameter and of purity 99.99% and by dischargingin an argon atmosphere of 1.0 Pa, with an RF output of 1.0 kW bysputtering.

Then, as shown in FIGS. 6C and 6D, an insulating film 606 is formed, inwhich portions of the first electrode 604 and the second electrode 605are each exposed and opened. Screen printing is employed for forming theinsulating film. Alternatively, the insulating film may be formed overthe entire face of the substrate by a CVD method or an applicationmethod, and then, a portion thereof may be etched to form contact holesso that each electrode, that is, the electrodes 604 and 605, is exposed.By opening the contact holes symmetrically, it is possible that anoptical sensor can be prevented from tilting when it is mounted on awiring substrate.

Electrode terminals 607 and 608 that are leading out electrodes areformed in contact holes where portions of the electrodes 604 and 605 areexposing respectively. The electrode terminals can be formed from aconductive film having a metal element such as silver, gold, copper,platinum, or nickel. In this embodiment, a leading out electrode of1.35×1.8 mm² is formed. In this embodiment, the electrode terminal isformed by using resin paste including copper with screen printing.

Next, an anisotropic conductive adhesive agent 609 is applied to entiresurface of a substrate, as shown in FIGS. 7A and 7B. In this embodiment,epoxy resin that silver particle is dispersed is applied. Note that, theanisotropic conductive adhesive agent is applied to the substrate byapplication method in this embodiment, but printing method, specificallyscreen printing method, may be used instead of this step. In case ofusing the screen printing method, an adhesive agent does not hinder whenthe substrate is diced, because the anisotropic conductive adhesiveagent is placed by taking off a dicing line to cut out an optical sensorlater.

Next, as shown in FIGS. 7C and 7D, an interposer 613 that connectionterminals (side electrodes) 611 and 612 are formed is placed on ananisotropic conductive adhesive agent. At this time, alignment iscarried out and the interposer 613 is set so as electrode terminals 607and 608 of an optical sensor to face the connection terminals (sideelectrodes) 611 and 612 that are formed in the interposer. Theinterposer is bonded to the substrate by thermo pressure bonding in thedirection of an arrow 614.

Next, the optical sensor is cut out by a laser scribe step. In thisembodiment, laser light is irradiated on a region that is parallel to aminor axis of the optical sensor and an optical sensor element is notformed (A-axis: 621 a to 621 d), and in a region that is perpendicularto the minor axis of the optical sensor (that is, parallel to a majoraxis of the optical sensor) and the optical sensor element is not formed(B-axis: 622 a to 622 e) in order to cut out the optical sensor. In thisembodiment, a YAG laser having an oscillation frequency of 1 kHz, awavelength of 1.06 μm, and a beam diameter (φ) of 60 μm is used toirradiate.

The optical sensor can be formed through the above-described steps.

In the semiconductor device according to the present invention, thesemiconductor element can be electrically connected to a connectionterminal (side electrode) of the interposer, therefore, an area to bejoined to the wiring substrate is increased. That is, a joining mode canbe checked with eyes, in addition that mounting intensity can be raised.Therefore, reliability in process can be raised. Moreover, thesemiconductor element is formed over the substrate, and a substrate areaand the region that serves as the semiconductor element is approximatelyequal. Therefore, the semiconductor device can be highly integrated overthe wiring substrate or the like.

Moreover, the connection of the semiconductor element and the interposeris strong since these two members are bonded in an aspect of an entiresurface facing each other. In addition, since the semiconductor elementand the interposer are connected to each other via resin, the cost canbe reduced. Moreover, resin has high fixing strength, and so thesemiconductor device having high breaking strength can be manufactured.

Embodiment 2

Various electronic devices can be manufactured by incorporating asemiconductor device obtained according to the present invention. Suchelectronic devices, a cellular phone, a laptop personal computer, agaming machine, a car navigation, a portable audio equipment, a handy AVequipment, a digital camera, a film camera, an instant camera, a roomair-conditioner, a car air-conditioner, a ventilation and airconditioning equipment, an electric pot, a CRT type projection TV, alighting equipment, lighting facilities, and the like. Specific examplesof the electronic devices are shown hereinafter.

An optical sensor of the present invention can be used in a cellularphone, a laptop personal computer, a digital camera, a gaming machine, acar navigation, a portable audio equipment, and the like, as a sensorfor optimally adjusting brightness of a display and a backlightilluminance, and saving a battery. A solar battery can be provided forthese devices equipment as a battery. The semiconductor devices can bedownsized and highly integrated, and thus, electronic devices can bemore downsized by using them.

The optical sensor of the present invention can be provided in a keyswitch of a cellular phone, and handy AV equipment as a sensor forcontrolling ON and OFF of a backlight LED and a cold cathode tube or asensor for saving a battery. By being provided with a sensor, a switchis turned OFF in a bright environment, and battery consumption by a longperiod of button operation can be reduced. Because a semiconductordevice of the present invention can be downsized and highly integrated,a more downsized electronic device and saving power consumption can beachieved.

Further, the optical sensor of the present invention can be provided ina digital camera, a film camera, and an instant camera as a sensor of aflash dimmer control or a sensor for an aperture control. In addition, asolar battery can be provided for these electronic devices as a battery.The semiconductor devices can be downsized and highly integrated, andthus, electronic devices can be more downsized by using them.

Moreover, the optical sensor of the present invention can be provided ina room air-conditioner, a car air-conditioner, and a ventilation and airconditioning equipment as a sensor for controlling airflow ortemperature. Because a semiconductor device of the present invention canbe downsized and highly integrated, a more downsized electronic deviceand saving power consumption can be achieved.

Moreover, the optical sensor of the present invention can be provided inan electric pot as a sensor for controlling a temperature for keepingwarm. After an indoor light is turned OFF, the temperature for keepingwarm can be set low by the optical sensor of the present invention.Since the optical sensor is small and thin, it can be provided at adesired position. Consequently, saving electric power can be achieved.

The optical sensor of the present invention can be provided in a displayof a CRT type projection TV as a sensor for adjusting a position of ascanning line (positioning of RGB scanning lines (Digital AutoConvergence)). Since the semiconductor device of the present inventioncan be downsized and highly integrated, the electronic device can bemore downsized by using it, and a sensor can be provided at a desiredposition. In addition, high-speed automatic regulation of the CRT typeprojection TV is possible.

The optical sensor of the present invention can be provided in variousdomestic lighting equipment, an outdoor lamp, a street light, anunmanned public utility, an athletic field, a car, a calculator and thelike as a sensor for controlling ON and OFF of various lightingequipment and lighting facilities. Electric power can be saved by thesensor of the present invention. A battery can be thinned to downsize anelectronic device by providing a solar battery according to the presentinvention for such electronic devices as a battery.

This application is based on Japanese Patent Application serial no.2003-347678 field in Japan Patent Office on Oct. 6, 2003, the contentsof which are hereby incorporated by reference.

What is claimed is:
 1. A method for manufacturing a semiconductor devicecomprising the steps of: providing a conductive film to a member so thata side surface, an upper surface, and a bottom surface of the member arecovered by the conductive film, bonding a semiconductor element providedon a substrate to the member using an adhesive joint member selectedfrom an anisotropic conductive adhesive agent or an anisotropicconductive film so that an electrode of the semiconductor element iselectrically connected to the conductive film; and mounting thesemiconductor element over a wiring substrate having an electrode padusing a solder so that a side surface of the conductive film is coveredby the solder.
 2. The method for manufacturing the semiconductor deviceaccording to claim 1, wherein the adhesive joint member includes aconductive particle.
 3. The method for manufacturing the semiconductordevice according to claim 1, wherein the substrate is a film-shapedsubstrate or a sheet-like substrate.
 4. The method for manufacturing thesemiconductor device according to claim 1, wherein the substrate is aglass substrate, a plastic substrate, or a substrate formed from organicresin.
 5. The method for manufacturing the semiconductor deviceaccording to claim 1, wherein the semiconductor element has a thin filmtransistor or a diode.
 6. The method for manufacturing the semiconductordevice according to claim 1, wherein the substrate has insulation. 7.The method for manufacturing the semiconductor device according to claim1, wherein the semiconductor device is an optical sensor, aphotoelectric conversion device, or a solar battery.
 8. The method formanufacturing the semiconductor device according to claim 1, wherein themounting of the semiconductor element over the wiring substrate isperformed so that the solder is in contact with and interposed betweenthe conductive film and the electrode pad.
 9. A method for manufacturinga semiconductor device comprising the steps of: providing a firstconductive film and a second conductive film to a member so that a sidesurface, an upper surface, and a bottom surface of the member arecovered by the first conductive film and the second conductive film,bonding a semiconductor element, which comprises a first electrode and asecond electrode and is provided on a substrate, to the member using anadhesive joint member selected from an anisotropic conductive adhesiveagent or an anisotropic conductive film so that the first electrode andthe second electrode are electrically connected to the first conductivefilm and the second conductive film, respectively; and mounting thesemiconductor element over a wiring substrate having a first electrodepad and a second electrode pad using a solder so that the firstconductive film and the second conductive film are electricallyconnected to the first electrode pad and the second electrode pad,respectively, wherein the mounting of the semiconductor element over thewiring substrate is performed so that a side surface of the firstconductive film and a side surface of the second conductive film arecovered by the solder.
 10. The method for manufacturing thesemiconductor device according to claim 9, wherein the adhesive jointmember includes a conductive particle.
 11. The method for manufacturingthe semiconductor device according to claim 9, wherein the substrate isa film-shaped substrate or a sheet-like substrate.
 12. The method formanufacturing the semiconductor device according to claim 9, wherein thesubstrate is a glass substrate, a plastic substrate, or a substrateformed from organic resin.
 13. The method for manufacturing thesemiconductor device according to claim 9, wherein the semiconductorelement has a thin film transistor or a diode.
 14. The method formanufacturing the semiconductor device according to claim 9, wherein thesubstrate has insulation.
 15. The method for manufacturing thesemiconductor device according to claim 9, wherein the semiconductordevice is an optical sensor, a photoelectric conversion device, or asolar battery.
 16. The method for manufacturing the semiconductor deviceaccording to claim 9, wherein the mounting of the semiconductor elementover the wiring substrate is performed so that the solder is in contactwith and interposed between the first conductive film and the firstelectrode pad and between the second conductive film and the secondelectrode pad.